Now the first tutorial is significantly more recent, and reflects how my code is currently set up. So I was wondering what is an appropriate way to adapt for multiple shadow maps while maintaining the style of the first approach?

Is there such a thing as a sampler2DShadowArray? (I couldn't find this via googling but perhaps it has another name)

The first tutorial (regular shadow mapping) is here but you'll have to scroll down to "Stratified Poisson Sampling" to see fragment shader code as it appears in the accompanying source code (It uses the 'texture' function, rather than the 'texture2D' function.

The second tutorial (cascaded shadow maps) is here but if you choose to look at the accompanying source code, there are a variety of shaders saved because the program lets you choose your fragment shader for a variety of options. The best one to look at would be "shadow_multi_leak_fragment.glsl".